Search results

Here is the design of a 2.4 GHz antenna that is ideal for amateur satellite communications. This antenna is easy to assemble because the design itself tolerates inaccuracies in the construction without really affecting performance.

Concise instructions on making a broadband helical antenna for 2.4GHz use, such as: 802.11b wireless networking 2.4GHz video links.

Plan of a helix antenna for 2 meter satellite use by VK5ZAI

An on-line javascript calculator and quite a few pictures to show how to make a helix antenna.

This article describes how to make a quadrifilar helix (QFH) antenna easily, from inexpensive materials: uPVC plumbing pipe and RG-58U co-axial cable. A low-cost, easy-to-build Quadrifilar Helix (QFH) antenna for weather satellite reception using uPVC plumbing pipe and RG-58U coaxial cable. Unlike traditional designs requiring copper pipe and plumbing skills, this approach enables construction with basic tools and minimal technical expertise. The antenna's shorter, wider proportions favor higher elevation angles, reducing interference from horizon-level pager transmitters. Electrical connections are simplified at the antenna's apex, with the coaxial cable forming the radiating elements. Testing demonstrated consistent signal strength throughout satellite passes, proving effective weather satellite reception is achievable without precision engineering to sub-millimeter tolerances.

Normal mode helix antennas offer a solution for HF mobile operators facing significant height restrictions, such as those parking in indoor garages with limited overhead clearance. This design, adapted from concepts typically applied to VHF/UHF rubber duck antennas, allows for extremely shortened HF radiators that remain effective for county hunting and general mobile operation. The resource details the construction of a 20-meter helix antenna, approximately 10 inches long, wound with #14 AWG THHN wire on a 1 1/2-inch CPVC form, mounted on a standard 3/8 x 24 antenna stud. Mark Herson, _N2MH_, shares his experience developing these antennas, including initial research from the _RSGB VHF UHF Manual_ and practical winding experiments to establish the relationship between turns and resonant frequency. He provides coil data for various frequencies, emphasizing that these measurements were taken with an _MFJ-259a_ antenna analyzer and are dependent on the vehicle's grounding system. Despite their shortened nature, N2MH confirms the antennas' operational effectiveness, citing contacts with KL1V in Alaska on 20 meters and E-skip contacts on 10 meters. The design prioritizes continuous deployment without removal, making it suitable for operators who frequently navigate height-restricted environments.

This design represents the smallest practical antenna for Oscar-13 mode-S. Perfect beacon reception at all times is possible, and acceptable SSB even at 43,000 km range.

This antenna is easy to build and suitable for broadband work, satellite work and terrestrial work.

A homebrew project of a quadruple helix antenna system based on G3RUH 16 turn helix antenna for 2.4 GHz.

Helix antenna calculator, to design and make helix antenna plans

Design your own quadrifilar helix, the site even generates a drilling pattern in a PDF file. Several different construction methods are shown.

This article describes how to make a quadrifilar helix (QFH) antenna easily, from inexpensive materials: uPVC plumbing pipe and RG-58U co-axial cable

This is an antenna that author just built. Was intend for receiving the AO-27 downlink (at 436.800 +/- doppler). It is built with right hand circular polarization, and the gain is supposed to be in the neighborhood of 3 DB.

homebrew an helix antenna for 435 MHz by VE2ZAZ

A helix will work in the normal mode when the diameter and pitch of the helix is less than 0.1 Lambda

Improved Helical Antenna Design for 802.11b WLAN by PA0HOO

by Dr. D.T. Emerson, National Radio Astronomy Observatory (NRAO++). Antenna Compendium Volume 4, pp 64-68, 1995, published by the ARRL.

Helical antennas invented by John Kraus give a circular polarized wave. They are one of the easiest to design. Find a tube with a circumference equal to one wavelength, and wrap wire in a helix spaced a quarter wavelengt

Presents a detailed construction guide for a **Quadrifilar Helix Antenna** (QHA) optimized for 137 MHz, specifically for receiving weather satellite transmissions. The resource outlines the author's experience building previous QHA designs, highlighting challenges with tuning and nulls, and then focuses on a refined design by John Boyer, documented by Steve Blackmore, which proved easier to build and yielded superior reception. The guide provides precise element dimensions, including 1.5m of 32mm PVC pipe for the mast and 8mm soft copper tubing for the helix elements. It specifies lengths for horizontal tubes (190mm, 90mm) and helix elements (903mm, 1002mm), along with instructions for drilling, assembly, and forming a **balun** by wrapping RG58 coax around the mast. The text emphasizes critical steps like ensuring elements are square and twisting in the correct direction to avoid phase issues. It includes references to original QST articles by Buck Ruperto (W3KH) and the WxSat program for decoding satellite transmissions, contextualizing the antenna's purpose. The article concludes with a sample NOAA 12 image from September 1998, demonstrating the antenna's reception capabilities.

Online helix antenna designer, calculate size of helix antennas online

This article summarizes probably the most extensive numerical modelling calculations on the helical antenna ever performed.

Notes on Axial-Mode Helical Antennas in Amateur Service. Helix Basics, Modeling Issues, and Short Helical Antennas Over Perfect Ground

DIY a Wi-FI Helical Antenna for better performances, a project by PA0HOO i Dutch end English

Helix antenna design and construction details

Helix antenna online calculator with match calculator

How to build a QFH (Quadrifilar Helix Antenna) to download images from weather satellites. A complete tutorial on assembling QFH antenna at home with simple and common tools

VE3NEA presents a detailed account of designing and constructing a **helical filter** specifically for 144 MHz satellite reception, addressing severe SDR receiver overloading from nearby Land Mobile Radio Network signals between 141 MHz and 143 MHz. The author's experience with RTL-SDR, RSP1a, and Airspy Mini receivers demonstrated the necessity of a narrowband solution to enable reception in the 145.8-146 MHz range with only 3 MHz separation from strong interference. The resource delves into the theoretical underpinnings of helical resonators, drawing upon Anatol I. Zverev's "Handbook of filter synthesis." It explains the equivalent circuit of a two-resonator passband filter, highlighting the critical role of stray capacitance (C3) in determining the coupling coefficient (K) and emphasizing the importance of **critical coupling** (K=1) for optimal filter performance. Misconceptions regarding tap positions and impedance transformation are clarified, with tap placement shown to control resonator loading and the trade-off between bandwidth and losses. Construction details include sourcing materials like 1/4" copper tubing and PCB, precise assembly techniques, and the use of tuning screws for frequency and coupling adjustments. Measurements performed with a NanoVNA revealed discrepancies from initial Coil64 calculations, necessitating adjustments to helix turns and tap positions to achieve the desired 3.5 dB passband loss and 40-50 dB suppression of interference.

This online calculator will give as output the Inductance L of a coil, including the total lenght of the wire needed to wound the coil. As input, requires the Diameter, number of turns, wire diameter and turn spacing

Article and video showing a technique to straighten Microbore copper pipe that is useful in antenna construction. This technique has been implemented to build a Quadrifiliar Helix antenna.

Helix antenna 432/435 MHz 14 turns. This 50 ohm impedance antenna allows, when fed with 25/50W of SSB RF, to join the orbiting satellites like AO-40 and AO-10 very easily

Receiving & Decoding NOAA Weather Satellites using a simple rtl-sdr dongle, a helix antenna and a Windows PC

Helical antenna or helix antenna is the antenna in which the conducting wire is wound in helical shape and connected to the ground plate with a feeder line. It is the simplest antenna, which provides circularly polarized waves.

This project details the construction of a compact, circularly polarized Quadrifilar Helix Antenna (QHA) designed for 146 MHz operation. The antenna features a 1/2λ1/2λ helical design with a 2.6:1 aspect ratio, providing 4.5 dB gain and a spheroid radiation pattern. It is ground plane independent and compatible with both vertical and horizontal polarizations, making it ideal for terrestrial and space communications. The design includes step-by-step instructions for building the antenna using readily available materials like aluminum rods, PVC pipes, and RG-58 coaxial cable. The antenna's performance has been validated through comparisons with commercial omnidirectional antennas, showing superior results.

This page provides information and links about Quadrifilar Helix Antennas, the best antenna for APT satellite reception. It explains the basic design and configuration of QHA, including the research and developments that have been made over the years. The page offers insights into the radiation patterns and benefits of using QHA for APT ground stations, with examples of polar diagrams. If you are interested in learning more about QHA and its applications, this page is a valuable resource.